The present invention relates to postage meters and more particularly to a postage meter system and process for calculating special fees to be added to postage for mailing an article. The term, "special fees," as used herein, includes of postal charges for registered mail, special delivery, return receipt, certified mail, insurance and cash on delivery (C.O.D.).
A number of different devices and systems have been developed to help a user determine the proper postage for mailing parcels. The simplest of these devices is, of course, a scale which provides a visual display of the parcel weight. The operator must translate this weight reading to a postage amount by resort to printed rate charts and special fee charts. The user than applies the postage to the parcel either in the form of stamps or in the form of an adhesive-backed tape printed with the user-calculated postage by means of a conventional postage meter.
This simple arrangement may be suitable for a conscientious user who mails few parcels over a given period of time. However, if the user isn't conscientious, he may misread the scale or misread the rate chart or use the wrong rate chart and incorrectly calculate the required amount of postage. If the postage which the user applies is insufficient, the parcel may be returned to its sender, delaying ultimate delivery. If the calculated postage is excessive, the parcel will be delivered but the user will have wasted his money. Moreover, this approach to mailing parcels is time consuming and cannot be effectively used where any significant number of parcels is to be mailed on a regular basis.
To reduce the chances of human error, it would be possible to develop a completely mechanical parcel metering system in which the displacement of a scale platform could be mechanically translated to a particular postage amount for a given class of service, i.e., domestic or international. The calculated postage could then be applied manually either in the form of stamps or a postage meter imprinted tape. The limitations of such a system are clear. The system would have to be kept simple by limiting its use to a particular class of service and by having no provision for determining special fee charges. The mechanical construction required to handle special fees would be incredibly complex, making such a device difficult to build and difficult to maintain. Moreover, a mechanical structure could not be easily updated to reflect the changes in postal rates or regulations.
Attempts have been made to overcome the above-discussed problems through the use of data processing technology and techniques for computation of postage.
For example, U.S. Pat. No. 3,635,297 generally discloses a postage calculator in which exact postage is said to be calculatable as a function of parcel weight, destination zip code and class of handling. The computer is said to include read only memory which stores postal zone information according to the first three digits of a destination zip code and postage rate information according to the combined parcel weight, zone and class of handling.
In U.S. Pat. No. 3,962,988, a postage calculator includes a postage memory which comprises a drum memory having weight increment indicia stored serially on a selected track of the drum. Adjacent tracks are grouped by zones or by specialized rate structures (such as library or book rate) with specific tracks within each group being dedicated to a particular class of service. Postage data for a particular class of service in a particular zone is stored as 16 serial bits of data occurring between successive pound increment indicia. The 16 bits are divided into four serially-occurring, four bit words with the most significant bit of the most significant word occurring first. The 16 bits of data are read out serially, divided into four bit words and decoded to yield a total postage value having up to four decimal digits. Generally speaking, it can be said that the drum memory stores a complete set of postage data for each different weight, destination zone and class of service.
Another postage calculator is disclosed in U.S. Pat. No. 4,047,006. In the system disclosed in this patent, postage data is stored in a plurality of individual storage sections, each of which is dedicated to one or more classes of postal service. Each storage section has a two dimensional array of storage locations. A first dimension address is defined by the destination zone for the parcel while a second dimension address is defined by the total parcel weight. The destination zone and class of service are manually entered to select one of the storage sections and to generate a destination address, which can be considered to be a function of both destination zone and class of service since not all classes of service have different rates for different postage zones. Data representing a required postage value for a package, exclusive of any special fees, is retrieved from the storage location defined by the intersection of the first dimension address and second dimension address.
Another postage calculator is disclosed in U.S. Pat. No. 4,139,892. In the system disclosed in this patent, a postage scale is used in conjunction with random access memories (RAM) and programmable read only memories (PROM) to perform a weighing operation. The postage calculation operation and a data display operation proceed according to various keyboard entries, including special service keys. No provision is made therein for determining whether special fees are mutually exclusive, nor is a method provided therein for subtracting previously added fees when a new, mutually exclusive fee must be calculated.
The prior art systems described above have certain common attributes. In each of the systems, stored data represents total postage values for different parcel weights, different destination zones and different classes of service. Moreover, the systems are generally limited to calculating postage for domestic mail service and provision for calculating special fees, if included, is rudimentary.
Since a significant amount of business involves the use of postal systems using one or more special fees, the prior art systems are not a solution to a sophisticated user's mailing problems. A user of one of the prior art systems must still resort to the use of printed rate charts to determine the proper postage for a package to be mailed with one or more special fees included, or he must begin the entire process of weighing and calculating again if two or more of the desired special fees are mutually exclusive. Moreover, the prior art systems cannot be readily extended to cover parcels mailed using mutually exclusive special fees without greatly increasing the amount of memory required for storage of total postage values. The larger memory needed increases the cost of the calculator.
Additionally, the prior art systems do not generally disclose any mechanism for taking peculiarities of the postal rate structure concerning conflicts, such as prohibiting the use of certain mutually exclusive special fees with each other or with a certain postal class, into account.